Portable electronic devices, such as those configured to be handheld or otherwise associated with a user, are employed in a wide variety of applications and environments. The ubiquity of such devices as mobile phones, wearables, including smart watches and glasses, digital still cameras and video cameras, handheld music and media players, portable video game devices and controllers, tablets, mobile internet devices (MIDs), personal navigation devices (PNDs), other APPlication acCESSORIES (or Appcessories for short) and other similar devices speaks the popularity and desire for these types of devices. Increasingly, such devices are equipped with one or more sensors or other systems for determining the position or motion of the portable device.
Information obtained from such sensors regarding motion of a portable device has been leveraged to provide information about the behavior and physical activity of a user. In turn, this information has been extensively applied in different fields such as navigation and localization, health monitoring, emergency services, athletic training, sport rehabilitation, elderly assistance and others. For example, indoor navigation systems benefit from knowledge about user motion and dynamics. In this context, such information may be used to select an appropriate movement model for a pedestrian, which can be used to limit the possible locations in combination with the other absolute positioning technologies, as well as to establish certain constraints that aid the navigation system. Motion sensors, such as accelerometers, gyroscopes, magnetometers and the like may be used to provide a basic indoor positioning solution for relatively short time periods when starting from a known position. Further, having information about the orientation of the device with respect to the user may increase the accuracy of a navigation solution. However, holding or fixing the device in a certain orientation so that it's orientation with respect to the user is known is unrealistic and inconvenient for the user. Thus, as a practical matter, portable devices including smartphones, tablets, smart watches, and smart glasses, etc. may be constrained or unconstrained in relation to the user such that the orientation of the device with respect to the user is not known.
Accordingly, it would be desirable to classify the current relationship between the device and the user, such as by determining how the device is being used, in order to gain insight into the potential relative orientation between the user and the device. Correspondingly, “device use case” as used herein refers to the type of interaction between a portable device and the user, and may include whether the user is carrying the device, holding the device with a swinging arm, positioning it “on ear” when talking, inputting data or viewing in a navigation or texting operation, carrying the device in a pocket or other container or holder, and other usages of the device that affect its orientation with respect to the user. Knowledge of the device use case may also provide other benefits. For example, a device use case not associated with active user engagement, such as being in a pocket, may allow improved management of operations being performed by the device, including the ability to enter power saving modes to save energy.
As will be described in the following materials, this disclosure satisfies these and other needs.